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Upland Grasslands (upland + grassland)
Selected AbstractsLiming upland grassland: the effects on earthworm communities and the chemical characteristics of carbon in castsEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 3 2008H. O. Bishop Summary Different earthworm species have different tolerances of acid soil conditions, and the application of lime to upland grassland to improve the grazing quality may therefore alter the size and diversity of the earthworm community. Altering soil properties may also affect the chemical characteristics of organic C in earthworm casts. We surveyed the earthworm community of an upland grassland in southern Scotland at the outset of annual lime applications, and after 3 years, and used 13C nuclear magnetic resonance (NMR) spectroscopy to assess the distribution of C between different functional groups in the organic matter. In addition, soil was incubated for 8 weeks with several earthworm species in the presence or absence of lime, and the earthworm casts were subsequently analysed by 13C NMR spectroscopy. Liming did not significantly affect earthworm abundance or species diversity, but it did affect the chemical composition of the casts. Casts from earthworms incubated in unlimed soil had greater ratios of alkyl-C to O,alkyl-C, indicative of more decomposed, recalcitrant C, and spectra from litter-feeding species had the greatest intensities of O,alkyl-C signals. In limed soil, the largest O,alkyl-C signal intensities were not restricted to litter-feeding species, indicating an increase in the quality of organic matter ingested by geophagous species. [source] Carbon flow in an upland grassland: effect of liming on the flux of recently photosynthesized carbon to rhizosphere soilGLOBAL CHANGE BIOLOGY, Issue 12 2004J. Ignacio Rangel-Castro Abstract The effect of liming on the flow of recently photosynthesized carbon to rhizosphere soil was studied using 13CO2 pulse labelling, in an upland grassland ecosystem in Scotland. The use of 13C enabled detection, in the field, of the effect of a 4-year liming period of selected soil plots on C allocation from plant biomass to soil, in comparison with unlimed plots. Photosynthetic rates and carbon turnover were higher in plants grown in limed soils than in those from unlimed plots. Higher ,13C, values were detected in shoots from limed plants than in those from unlimed plants in samples clipped within 15 days of the end of pulse labelling. Analysis of the aboveground plant production corresponding to the 4-year period of liming indicated that the standing biomass was higher in plots that received lime. Lower ,13C, values in limed roots compared with unlimed roots were found, whereas no significant difference was detected between soil samples. Extrapolation of our results indicated that more C has been lost through the soil than has been gained via photosynthetic assimilation because of pasture liming in Scotland during the period 1990,1998. However, the uncertainty associated with such extrapolation based on this single study is high and these estimates are provided only to set our findings in the broader context of national soil carbon emissions. [source] How does grazing intensity influence the diversity of plants and insects in a species-rich upland grassland on basalt soils?GRASS & FORAGE SCIENCE, Issue 1 2009B. Dumont Abstract The effect of stocking rate on the species richness, abundance and functional diversity of vascular plants, butterflies and grasshoppers was examined in a semi-natural upland pasture in central France. Over a 5-year period, 3·6-ha plots were continuously grazed by Charolais heifers at 1·4 (High stocking rate), 1·0 (Intermediate) and 0·6 (Low) livestock units (LU) ha,1. To evaluate botanical diversity, percentage cover of all plant species was estimated in late July in ten fixed 1 m × 1 m quadrats per plot. Butterflies were counted on three occasions between late June and early August along three fixed 50-m-long transects per plot using the ,Pollard walk', with grasshoppers being recorded on two occasions along the same transects. Diversity patterns of the three taxa were affected by stocking rate. For plants, species abundance changed more than species number. Abundance of forbs became higher under the Low compared with the High stocking rate. Stress-tolerant grasses were also more abundant in plots grazed at the Low stocking rate, while an opposite trend was observed for competitive grasses. Butterflies consistently responded to alterations in vegetation composition, especially to the dynamics of nectar plants. The species richness of grasshoppers also increased in plots at the Low stocking rate. The Low and Intermediate stocking rates were suitable for providing a high diversity of the three taxonomic groups. The results suggested that at least butterfly diversity would peak in vegetation taller than that of vascular plants. [source] Characterization of diverse plant communities in Aspen Parkland rangeland using LiDAR dataAPPLIED VEGETATION SCIENCE, Issue 3 2007Jason G. Su Moss (1983) Abstract Question: How effective is high-resolution airborne LiDAR technology for quantifying biophysical characteristics of multiple community types within diverse rangeland environments? Location: Native Aspen Parkland vegetation in central Alberta, Canada. Methods: Vegetation within 117 reference plots stratified across eight types, including forest, shrubland, upland grassland and lowland meadow communities, were assessed in 2001 for the height, cover and density of vegetation within various strata (herb, shrub and tree layers). Actual ground data were subsequently compared against modelled values for each community type and strata derived from the analysis of airborne LiDAR data obtained in 2000. Results: LiDAR data were effective for quantifying vegetation height, cover and density of the overstory within closed- and open Populus forest communities. However, LiDAR measurements typically underestimated the height and cover of shrublands, as well as most of the herbaceous communities. Analysis of LiDAR intensity data indicated reflectance generally decreased as LiDAR sampling points moved upwards from the ground to the vegetation canopy. Conclusions: While LiDAR technology is useful for characterizing deciduous forest properties, the quantification of understory vegetation characteristics, as well as those of individual shrublands and grasslands, was more limiting. Further refinements in analysis methods are necessary to increase the reliability of characterizing these communities. [source] Seasonal and management influences on bacterial community structure in an upland grassland soilFEMS MICROBIOLOGY ECOLOGY, Issue 3 2005Nabla M. Kennedy Abstract Floristically diverse Nardo,Galion upland grasslands are common in Ireland and the UK and are valuable in agricultural, environmental and ecological terms. Under improvement (inputs of lime, fertiliser and re-seeding), they convert to mesotrophic grassland containing very few plant species. The effects of upland grassland improvement and seasonality on soil microbial communities were investigated at an upland site. Samples were taken at five times in one year in order to observe seasonal trends, and bacterial community structure was monitored using automated ribosomal intergenic spacer analysis (ARISA), a DNA-fingerprinting approach. Differences in soil chemistry and bacterial community structure between unimproved and improved grassland soils were noted. Season was also found to cause mild fluctuations in bacterial community structure, with soil samples from colder months (October and December) more correlated with change in ribotype profiles than samples from warmer months. However, for the majority of seasons clear differences in bacterial community structures from unimproved and improved soils could be seen, indicating seasonal influences did not obscure effects associated with improvement. [source] Consequences for biodiversity of reducing inputs to upland temperate pastures: effects on beetles (Coleoptera) of cessation of nitrogen fertilizer application and reductions in stocking rates of sheepGRASS & FORAGE SCIENCE, Issue 2 2004P. Dennis Abstract Current policies for upland pasture management in the UK encourage the integration of environmental objectives with livestock production through extensification of grazing systems. This study tested the hypothesis that a greater sward height in the summer would increase the diversity and abundance of grassland beetles (Coleoptera) as has been demonstrated for insects of indigenous grasslands. The hypothesis was tested with an experiment on an upland sheep pasture in mid-Wales. Experimental treatments received different nitrogen fertilizer inputs (0 or 50 kg ha,1), sheep stocking densities (12 or 9 ewes ha,1) and average sward heights in summer were constrained to 3·5 or 5·5 cm by conserving surplus grass for silage in subplots. Five treatments, replicated in three randomized blocks, combined the two stocking densities and two sward heights without nitrogen fertilizer inputs, with the fifth combining the higher stocking density, shortest sward height and the nitrogen fertilizer input. Beetles were sampled with twelve pitfall traps in each of the fifteen plots from June to September in 1993 and 1995. In years 1 (1993) and 3 (1995) of the experiment, more Coleoptera species occurred in the tall sward (an average of nine species in addition to the forty-one species present in the sward with the conventional sward height). Continuously grazed as opposed to ensiled subplots supported more beetle species but fewer individuals. Species composition of ground (Carabidae) and rove (Staphylinidae) beetles varied between treatments more than the arithmetic differences in species number. The experimental results supported the hypothesis but the benefits of taller swards to species diversity were small in the sown pastures of the study compared with indigenous upland grasslands (c. 33% fewer species). Inheritance effects of drainage, fertilizer and lime inputs, and the different species and management of cultivated pastures, may constrain the conservation benefits of altered pasture management compared with indigenous grasslands. [source] Variation in the use of pasture by breeding European Golden Plovers Pluvialis apricaria in relation to prey availabilityIBIS, Issue 3 2003J. W. Pearce-Higgins European Golden Plover Pluvialis apricaria populations have declined across Western Europe. Changes to upland grasslands that are utilized by foraging off-duty birds may have contributed to this decline. The use of enclosed agricultural land by a stable breeding population of Golden Plovers in the South Pennines is described to examine this hypothesis. Fields contained foraging plovers from the end of February to the end of July. Off-duty incubating birds commuted to feed on fields, females during the day and males at night. During the day, adults flew from 6.6 to 7.2 km from the nest to feed, whilst at night birds commuted from 2.4 to 2.7 km. The length of time spent foraging by males was inversely dependent upon daylength. Following hatching, the use of pasture declined, although not as much as in other studies. Arable and improved fields received most use by 15 radiotagged birds, whilst the use of pasture throughout the breeding season was negatively correlated with sward height. Adult diet consisted largely of subsurface prey, particularly larval tipulids, although earthworms were an important component in March and April. The biomass of larval tipulids was strongly correlated with an index of the use of fields. The selection of fields by Golden Plovers is therefore dependent upon prey abundance and availability, and, consequently, is likely to be enhanced by summer grazing and poor drainage. These findings are discussed in the light of recent trends in pastoral management. [source] Can grazing response of herbaceous plants be predicted from simple vegetative traits?JOURNAL OF APPLIED ECOLOGY, Issue 3 2001Sandra Díaz Summary 1,Range management is based on the response of plant species and communities to grazing intensity. The identification of easily measured plant functional traits that consistently predict grazing response in a wide spectrum of rangelands would be a major advance. 2,Sets of species from temperate subhumid upland grasslands of Argentina and Israel, grazed by cattle, were analysed to find out whether: (i) plants with contrasting grazing responses differed in terms of easily measured vegetative and life-history traits; (ii) their grazing response could be predicted from those traits; (iii) these patterns differed between the two countries. Leaf mass, area, specific area (SLA) and toughness were measured on 83 Argentine and 19 Israeli species. Species were classified by grazing response (grazing-susceptible or grazing-resistant) and plant height (< or > 40 cm) as well as by life history (annual or perennial) and taxonomy (monocotyledon or dicotyledon). 3,Similar plant traits were associated with a specific response to grazing in both Argentina and Israel. Grazing-resistant species were shorter in height, and had smaller, more tender, leaves, with higher SLA than grazing-susceptible species. Grazing resistance was associated with both avoidance traits (small height and leaf size) and tolerance traits (high SLA). Leaf toughness did not contribute to grazing resistance and may be related to selection for canopy dominance. 4,Plant height was the best single predictor of grazing response, followed by leaf mass. The best prediction of species grazing response was achieved by combining plant height, life history and leaf mass. SLA was a comparatively poor predictor of grazing response. 5,The ranges of plant traits, and some correlation patterns between them, differed markedly between species sets from Argentina and Israel. However, the significant relationships between plant traits and grazing response were maintained. 6,The results of this exploratory study suggest that prediction of grazing responses on the basis of easily measured plant traits is feasible and consistent between similar grazing systems in different regions. The results challenge the precept that intense cattle grazing necessarily favours species with tough, unpalatable, leaves. [source] Pattern and process in Norwegian upland grasslands: a functional analysisJOURNAL OF VEGETATION SCIENCE, Issue 1 2002Vigdis Vandvik Lid & Lid (1994) Abstract. Four classes of functional and morphological plant traits , established strategies (the CSR scheme sensu Grime 1979), life-forms (sensu Raunkiaer 1934), morphology, and regenerative strategies , are used as tools for explaining vegetation gradients at summer farms in the mountains of western Norway. These farms are assembly points for free-ranging domestic grazers, and differ floristically and ecologically from the surrounding heath or woodland vegetation. DCA and TWINSPAN are used to relate major gradients in a floristic data set from 12 summer farms to two sets of explanatory variables: (1) environmental variables representing physical factors, plot position, soils, and land use, and (2) the 4 classification schemes. The main floristic gradient parallels a spatial gradient from the centres of the farms to the surrounding vegetation. A functional interpretation based on the concurrent use of the 2 sets of explanatory variables suggests that the gradient is one of decreasing disturbance and increasing environmental stress caused by decreasing grazing and manure effects away from farms. Partial CCA is used to investigate the relationships between the 4 functional/morphological plant trait classes. The 4 classification schemes are partially redundant, and do not represent different trends of specialization within the landscape. There is no strong evidence for decoupling of the traits of the vegetative and regenerative phases within the data. The combination of general process-based theories and specific plant attribute responses enhances the generality and interpretability of the study. [source] Nutrient concentration ratios and co-limitation in South African grasslandsNEW PHYTOLOGIST, Issue 3 2008Joseph M. Craine Summary ,Assessing plant nutrient limitation is a fundamental part of understanding grassland dynamics. The ratio of concentrations of nitrogen (N) and phosphorus (P) in vegetation has been proposed as an index of the relative limitation of biomass production by N and P, but its utility has not been tested well in grasslands. ,At five sites in Kruger National Park, South Africa, across soil and precipitation contrasts, N and P were added in a factorial design to grass-dominated plots. ,Although the N:P ratio of unfertilized vegetation across all sites (5.8) would have indicated that production was N-limited, aboveground production was consistently co-limited by N and P. Aboveground production was still greater in plots fertilized with N and P than in those fertilized with just N, but the N:P ratio did not exceed standard thresholds for P limitation in N-fertilized vegetation. Comparisons among sites showed little pattern between site N:P ratio and relative responses to N and P. ,When combined with results from other grassland fertilization studies, these data suggest that the N:P ratio of grasses has little ability to predict limitation in upland grasslands. Co-limitation between N and P appears to be much more widespread than would be predicted from simple assumptions of vegetative N:P ratios. [source] | |||||||||||||